Chapter 18: Water Pollution

Red Tides

A red, orange, or brown coloration of water caused by a bloom, or population explosion of algae; many cause serious environmental harm and threaten the health of humans and animals -dinoflagellate blooms -have become increasingly common in slow-moving and shallow waters

Is Bottled Water Safer?

-Americans buy 28 billion bottles of water annually -Adds up to around $15 billion -Worldwide =42 billion gallons -Municipal water is often safer than bottled because most large cities test their water supplies every hour for up to 25 different chemicals -80% of water bottles purchased in the United States end up in landfills

Groundwater Is Hard To Monitor And Clean

-About half the U.S. population, and 95% of rural residents, depend on underground aquifers for drinking water -For decades, groundwater was assumed impervious to pollution and artesian well water was considered the definitive standard for water quality, but that is no longer true

Main Sources of Nonpoint Pollution

-Agriculture -Urban runoff -Construction sites -Land disposal -Generally, soil conservation methods also help protect water quality -In urban areas, reducing materials carried away by storm runoff is helpful

Water Treatment

-Between 1990 and 2010, more than 2 billion people gained access to "improved" water. Most progress was in China and India -Improved water supplies are tube wells, water piped from clean sources, and treated water

How To Reduce Water Pollution Production

-Cheapest and most effective way to reduce pollution is avoid producing it or releasing it into the environment -Studies show as much as 90% less road salt can be used without significantly affecting safety -Carefully dispose of oil -Recover metals from industrial waste and sell them -Elimination of the use of lead in gasoline led to a significant decline of lead in US surface waters

Few Controls on Ocean Pollution

-Coastal zone (for example, bays, estuaries, reefs) often overwhelmed by contamination from heavy metals, toxic chemicals, oil, pathogens, sediment. These zones would otherwise be among the most productive -Discarded plastics are non-biodegradable, last for years, and are carried by currents around the world -Often ensnare bird and mammals, choking them

Water Remediation

-Containment methods confine liquid wastes in place, or cap surface with impermeable layer to divert water away from a site that is causing pollution -Extraction techniques are used to pump out polluted water for treatment -Oxidation, reduction, neutralization, or precipitation of contaminants

CERCLA (1980)

-Created Super-fund program to clean up toxic waste sites -Amended in 1984 by SARA, which provides immediate response in emergency situations and permanent remedies for abandoned sites

Clean Water Act (1972)-Areas of Contention

-Draining or filling of wetlands is regulated by Section 404 -Farmers and developers consider this the taking of private lands

Clean Water Act (1972)

-Established a National Pollution Discharge System which requires a permit for any entity dumping wastes in surface waters and requires disclosure of what is being dumped -Improvement in water quality, mostly due to sewage treatment -The goal of making all U.S. surface waters "fishable and swimmable" hasn't been fully me

Groundwater and Drinking Water

-Estimates 4.5 trillion liters (1.2 trillion gal) of contaminated water seep into the groundwater in the U.S. every day -Comes from septic tanks, cesspools, landfills, waste disposal sites, etc -1 gal of gasoline can make 1 million gal of water undrinkable -In agricultural areas, fertilizers and pesticides commonly contaminate aquifers and wells -Contaminants remain for thousands of years -In addition to groundwater, contaminated surface waters can make drinking water unsafe -2008 EPA data show that 30 million people in the U.S. get water from community systems that don't meet all health-based drinking water standards -An estimated 1.5 million Americans fall ill from fecal contamination annually -Preventive measure costs far less than paying for the health care costs associated with polluted water

U.S. Clean Water Act (1972)

-Goal was to return all U.S. surface waters to "fishable and swimmable" conditions -For point sources, discharge permits and best practicable control technology (BPT) are required -Set goals of best available, economically achievable technology(BAT) for zero discharge of 126 priority toxic pollutants

Sediment

-Human activities have accelerated erosion rates in many areas -Human-induced erosion and runoff contribute about 25 billion metric tons of sediment and suspended solids to world surface waters each year -Obstructs shipping channels, clogs hydroelectric turbines, smothers fish eggs, blocks out light needed for photosynthesis -Sediment can also be beneficial for example, building coastal wetlands and nourishing floodplain fields

Low Cost Waste Treatment-Effluent Sewerage

-Hybrid between traditional septic tank and full sewer system -Pump liquid tank contents to central treatment plant rather than use drain-field

What are the two most important sources of toxic organic chemicals in water?

-Improper disposal of industrial and household wastes -Runoff of pesticides from fields, roadsides, golf courses, and lawns

Areas of Progress

-In 1998, EPA switched regulatory approaches. Rather than issue standards on a site by site basis, the focus is now on watershed-level monitoring and protection -States are required to identify waters not meeting water quality goals and developtotal maximum daily loads (TMDLs)for each pollutant and each listed water body

Infectious Agents in water

-Main source of waterborne pathogens is improperly treated human waste -Animal waste from feedlots and fields is also important source of pathogens -At least 2.5 billion people in poor countries lack adequate sanitation -780 million lack access to clean drinking water -In wealthier countries, sewage treatment plants and pollution-control devices have greatly reduced pathogens

CSOs

-Many U.S. cities, sanitary sewers are connected to storm sewers -Heavy storms can overload the system, causing by-pass dumping of raw sewage and toxic runoff directly into surface water

Inorganic Pollutants-Nonmetallic Salts

-Many salts (including those selenium and arsenic-based) that are non-toxic at low concentrations can be mobilized by irrigation and concentrated by evaporation, reaching levels toxic to plants and animals -Leaching of road salts has had detrimental effect on many ecosystems -Arsenic in northeastern India and western Bangladesh groundwater

Inorganic Pollutants-Metals

-Mercury, lead, cadmium, tin and nickel are highly toxic -Highly persistent and tend to bioaccumulate in food chains -Most widespread toxic metal contaminant in North America is mercury (found in fish) -600,000 American children have mercury levels high enough to cause mental and developmental problems and 1 woman in 6 has blood levels high enough to harm fetus -Mine drainage and leaching of mine wastes are serious sources of environmental contamination

Human Waste Disposal

-More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water

Ecological Engineering

-Ocean Arks International designs vessels that combine living organisms with containment. In a machine, water flows through a series of containers, each with a distinctive biological community. Waste from one vessel becomes the food for the next vessel -Final effluent is technically drinkable, but more often used for irrigation or flushing toilet

Human Waste Disposal In Poor Countries

-Outdoor urination and defecation is the norm -When population densities are low, natural processes can quickly eliminate waste, but in cities this is unworkable -A significant proportion of dust in Mexico City is actually dried feces

Thermal Pollution

-Raising or lowering water temperatures from normal levels can adversely affect water quality and aquatic life -Oxygen solubility in water decreases as temperature increases -Species requiring high oxygen levels are adversely affected by warming water -Humans cause warming by discharging heated water from power plants and other industries -Industrial cooling processes use heat-exchangers to extract excess heat, discharge heated water back into original source as a thermal plume

Acids

-Released as byproducts of industrial processes -Coal mining is an especially important source of acid water pollution -Many streams acidified by acid mine drainage are lifeless -Combustion of fossil fuels releases sulfuric and nitric acids that are deposited in water -Thousands of lakes in northeastern US and Canada are empty of fish and support only a few mosses and fungi due to low pH

CSOs steps

-Screening (removes large solids) -Settlement Tanks (removes most of the remaining solids) -Bacteria (in beds or tanks purify the solids) -Water (returning to the environment) (the water may be disinfected with ultraviolet light) -Solids and sludge are treated and sent to a landfill or incinerator, and sometimes sold as a fertilizer

Water Pollution in other countries

-Sewage treatment in wealthier countries of Europe generally equals or surpasses the U.S -In Russia, only about half of the tap water supply is safe to drink and in China 70% of surface waters are unfit for consumption -The Yamuna River and ⅔of the other surface waters in India are so polluted that it is dangerous to even have contact with the water

Remaining Problems

-Some of the greatest impediments to achieving national goals in water quality are sediment, nutrients, and pathogens, especially from non-point discharges -About three-quarters of water pollution in the U.S. comes from soil erosion, air pollution fallout, and agricultural and urban runoff -Cattle in feedlots produce 144 million tons of manure -Pet waste does not go through sewage treatment

Clean Water Act (1972)-Unfunded Mandates

-State or local governments must spend monies to comply with regulations but are not repaid by Congress -Agricultural runoff and urban nonpoint pollution are the largest sources of surface water degradation, but regulation remains a problem

Human Waste Disposal and Water

-Until about 70 years ago, most rural areas in the U.S. depended on outhouses, which contaminated drinking water supplies -Development of septic fields

Oxygen-Demanding Waste

-Water with an oxygen content > 6 ppm will support desirable aquatic life -Water with < 2 ppm oxygen will support mainly detritivores and decomposers -Oxygen is added to water by diffusion from wind and waves, and by photosynthesis from green plants, algae, and cyanobacteria -Oxygen is removed from water by respiration and oxygen-consuming processes -Effects on rivers depend on volume, flow, and temperature of river water

Thermal Plume

A plume of hot water discharged into a stream or lake by a heat source, such as a power plant.

Biochemical Oxygen Demand

Amount of dissolved oxygen consumed by aquatic microorganisms. Used as a test for organic waste contamination from sewage, paper pulp and food waste

Water pollution/pollution

Any physical, biological, or chemical change in water quality that adversely affects living organisms or makes water unsuitable for desired uses

Resource Conservation and Recovery Act (1976)

Cradle to grave tracking of haz materials CERCLA(1980) created Superfund program to clean up toxic waste sites•Amended in 1984 by SARA, which provides immediate response in emergency situations and permanent remedies for abandoned sites

Infectious Agents

Bacteria, viruses, parasites

Secondary Treatment

Biological degradation of dissolved organic compound -Effluent from secondary treatment is usually disinfected (chlorinated) before release into nearby waterway

Eutrophic

Bodies of water that are rich in organisms and organic material

Oligotrophic

Bodies of water that have clear water and low biological productivity

Septic Fields

Clean water by aeration and remove excess nutrients through bacterial action -Solids are pumped out and taken to a treatment plant

Atmospheric Deposition

Contaminants carried by air currents and precipitated into watersheds or directly onto surface waters as rain, snow or dry particles -Estimated 600,000 kg of the herbicide atrazine in the Great Lakes -Most thought to have been deposited from the atmosphere -Contaminants can also evaporate from la

Point Sources

Discharge pollution from specific locations -Factories, power plants, drain pipes

Low Cost Waste Treatment-Natural or Artificial Wetlands

Effluent flows through wetlands where it is filtered and cleaned by aquatic plants and microscopic organisms

Night Soil

Human and animal waste -Spread on fields as fertilizer, but it can cause disease -Mainly in Asia

Cultural Eutrophication

Increase in biological productivity caused by human activities -Algal "blooms" often result and the decomposition of the algae depletes oxygen in the water

Coliform bacteria

Intestinal bacteria; used to detect water contamination by animal wastes -Drinking water generally disinfected via chlorination

Bio-remediation

Living organisms (for example, duckweed) can also be used to break down pollution in a process

Dissolved Oxygen Content

Measure of dissolved oxygen in the water

Oxygen Sag

Oxygen decline downstream from a pollution source that introduces materials with high biological oxygen demands -Oxygen levels decline downstream from a pollution source as decomposers metabolize waste materials

Primary Treatment

Physical separation of large solids from the waste stream -Effluent from primary treatment transferred into trickling bed, or aeration tank

Eutrophication

Process of increasing nutrient levels and biological productivity, a normal part of successional change in most lakes

Acid Mine Drainage

Reddish-orange iron precipitate is commonly seen in streams affected by acid mine drainage

Safe Drinking Water Act

Regulates water quality in municipal and commercial system

Tertiary Treatment

Removal of plant nutrients (nitrates and phosphates) from secondary effluent -Chemicals which bind or natural wetlands

Non-Point Sources

Scattered or diffuse, having no specific location of discharge -Agricultural fields, feedlots, golf courses, residential construction sites

Dinoflagellates

Single-celled organisms that swim with 2 whip-like flagella -Pfiesteria piscicidais a toxic dinoflagellate recently recognized -Found in marine zones that are polluted due to eutrophication

Organic Chemicals

Thousands of natural and synthetic organic chemicals are used to make pesticides, plastics, pharmaceuticals, pigments, and many other day to day products